Last year I almost spent $5000 on gas for the roadster and started making changes to my car as the prices kept creeping up. The initial mileage for the Dual Quad 455 Olds was around 12 mpg with the 2.74 gears and 14 mpg with the 2.18 gears but I had to run 80mph+ to be happy! Then I went to a progressive linkage for the dual quad and obtained 14 -16 mpg with the 2.74 gears. I finally met my goal mileage of 20 mpg by switching out the Turbo 400 with a 700R4 and 3.59 gears! But I don't have an accurate performance data because all the local NHRA tracks won't let me run until I cage my car... but Hopefully I can make a p*** at Mokan!
I grew up in a transmission shop and make my living rebuilding automatic transmissions. If you are wanting tow with this vehicle you do not want a 700 or a 4L60E you will burn up a 3-4 clutch. I strongly recommend finding a 4L80E.
twinturbo496, How is the oil pressure controlled with no computer? When there is no power to the EPC solenoid that trans goes to full line pressure. Does yours bang like hell when you put it in reverse? And with no computer how are the shift solenoids turned on and off for your shifts? Just really curious about what all you got goin on? Converter clutch is also electronic and it is not on/off it is a PWM (pulse width modulated) converter. How is your lock up controlled?
I tried, and OD didn't help my MPG much. I tried 3:70, 4:10 and 4:57 gears with stock tires and 245/70X19.5 tires. 7.4 TBI with T400 trans. Also installed a gear vendors OD. With no trailer I got a best of 12 mpg and a worst of 11, which tells be that it takes more fuel to push these things through the air than it does to spin the engine. Speed made the biggest difference, with the trailer (see photo) I got 7.5 mpg at 60 and 6.5 at 70. After I put the GV in I switched to a 5:38 gear. That gives me the same overall ratio in OD as a 4:56 in direct, which allows me to use the OD as a gear splitter which makes a HUGE difference in driveability with the trailer. 3rd direct W/ 5:38s is like halfway between 3rd and 2nd w/4:57s, which is perfect on hills at 55-60, and is not as big a drop as going all the way down to 2nd and needing to scream the motor. And putting the shifting stress on the GV is a good thing because it's way more rugged than the trans. I didn't go with a 4L80E because the OD RPM drop is much greater which is OK for a car or an empty truck, but way too much for a loaded truck, plus I wouldn't be able to split shift it. Before I put the OD in, it was lugging at 60 MPH when towing and didn't respond to the pedal in traffic until I was going 70 MPH. That was with 4:10s, it was much better with the 4:57. That's why I went with 5:38s and the GV - I saw there was little MPG to be gained with a taller ratio and lots of driveablilty to be lost.
I don't build transmissions for a living, but I rebuilt mine as follows: complete used transmission from a motorhome: $400 (I paid too much) Modified converter (Superior Converter in Portland, OR) $150 Clutches, gaskets, ... $220 NOTE: (Red Alto friction, probably not worth the money) Transgo-3 kit (includes a vacuum modulator like at TH400): $260 from Oregon Performance Transmission Total just over $1000, and yes, I have a push ****on on the shifter to lock the converter, no computer required. Note: Anyone who has a engine with over 800 hp should not use a modified stock converter. look at www.ls1tech.com for vendors like Circle D in Houston who have a multi disk converter up to 5000 rpm that will lock under full load. Line pressure is controlled by a modified TH400 vacuum modulator. no kickdown cable. The inside of this transmission is not much different than a TH400, the Transgo kit deletes all of the computer ****.
Note: I ran my car on the dyno in 3rd gear with the converter locked, a new stock converter clutch disc will hold at least 580 rwtq from 2500-4500.
I didn't want/have/need a computer to control the converter with a PWM, so I went to radio shack and got some resistors. I had to play around with it for a while, but for about $10.00 I ended up with four resistors in parallel, providing just enough current to the tcc to lock it, but not burn up the coil.
That's really interesting info Craig. Are you running an LS engine in your car? I co-founded LS1TECH back in 2001. I've been pondering putting a 4L80E and a 5.3 truck motor in my '51 merc along with a MP112 Magnuson supercharger.
The shift solenoids can take full 12 volts. Its just a switching combination to make them work. You can have full line pressure or current limit it with resistors as said before. You can also build a small PWM for a small amount. The cool thing is you put it in drive then push ****ons like an air shifted trans. You down shift the same way. Relays and switches will cost a bunch less than a computer box. The shop manual gives the combos for the A and B solenoids and resultant gears. Trans shops have a box called the schaffer shifter that is just a box with switches and a few electronics. You drive the 4L60E or 4L80E off the box.
the 4l80 seems to be much stronger than the 60 i have replaced much fewer 80's at work, although they are a little less common than the 60's so that may have more to do with it
All duly noted. However: 1. I have a one-car open trailer, not anything even close to what you're rolling, and hope I never need a trailer as big / heavy as yours. 2. Gear Vendors, from what I've read on "other websites" is no longer producing new OD boxes, and only sells old stock units produced up through the mid-90's. No product support, no spare parts, no nothing. A guy on one of the truck sites needed a controller and wiring harness and found out the hard way. I tried emailing them and didn't get a reply. As seldom as I tow, and what I usually tow, I'd trade down to a half-ton late model LSX truck with a factory 4L80E before buying a high-dollar overdrive box with no support after the sale.
I towed a ton of things with a beat up '89 Suburban with a 700R4, I just stuck a big second cooler on it and only towed in D, and it still runs and drives fine even though it rotted so bad I retired it to lot truck about 4 months ago. Once had about 7500 lbs behind it that I had to drag six miles up hill all the way, most of the time I kept it lower, either flat towing cars or occasionally cars on a trailer. You can tow with the 700R4 if you're not going to do it constantly and do it with some care. It will probably reduce the life of the trans over not towing, but that truck has just shy of 100K on it and that ***umes that it was 56K when I got it and not 156K. But they won't stand up to super high torque unless you have one purpose built, even the stock GM 6.2 diesel puts out enough torque that it can give them problems. They're not a good choice for something you really want to beat on. With regard to the 4L80E - if you can swap into one for a few bucks, it picks you up even a couple MPG, and you plan to drive the wheels off your car, chances are the savings in gas will make it pay for itself sooner or later.
I do, and would add that we've towed a 25ft, 4,000lb travel trailer at least 20K miles with the '48 Pontiac convert, which has an LT1/4L60E. The engine/trans had 70K on the clock when I installed it and it's got 110K now. Based on the great performance of that junkyard combo, yanked from a totalled Caddy Fleetwood, that the 350TBI/4L60E '93 van combo would be fine in my Diamond T. It'll be driving a Dana 70 4.10 rear. I'm pretty comfortable using the 4L60E as a tow vehicle trans, with a small, light trailer like ours. I'd just like to get rid of the computer control and wiring harness, which will be almost impossible to hide in the Diamond T's engine bay. That's my concern. Brian
I've towed with 4L60E's, no problems. But if I was doing a trans from scratch, I'd look pretty seriously at the 4L80E so long as I knew how I was going to control the transmission.
Is there a 4l60 or 4l80 that will bolt to a 1970's Cad 472 without an adapter? What else would I need?
nope, they all have the Chevy bolt pattern, you'll need an adapter plate. 200-4R will bolt to a Caddy.
So my daily driver 46 coupe with a 6" chop and a home built blown 496 that runs 11.05 @ 125 isn't a hot rod? I also own a torsion tube doug nash 5 speed crash box with a hurst V-gate, if I put it in my car and it runs slower at the drag strip , does that make it a real hot rod? See attached for the mock up with the doug nash.
Quickie OT question. My 68 jeepster has a th400. Is the tail shaft and housing on an l480e the same (or kinda close) to a 400? would make the swap to an overdrive a heluva lot less costly I wouldn't have to get a new xfer case adapter.
No, blown tall deck from a 1975 dump truck (427) with a 4.25 crank for 496 inches. my wife has an 05 GTO, that is why I found LS1 tech. She only owes another 3K on the GTO, then it gets a new maggie blower !!!
Your TH400 may be the one with the case that bolts up to a '57-up Buick nailhead. Those were a short tail trans because they usually went into a 4x4 transfer case, you needed the short tail housing and the right yoke to convert to 2WD. How to tell: There's a short bell between the trans case and the block. The trans itself has a fairly circular bolt pattern and the case isn't as deep at the front. If that's the case, you'd need a BOP to Chevy adapter to bolt the 4L80E to your motor (I ***ume it's a Jeep with a Buick V6 or 350?). The tailshaft is a tad longer per earlier posts, but if you got the trans with a yoke, it shouldn't be a big deal to make it work. Someone mentioned the 200R4 will bolt to a Caddy 472 - but how long is it going to last behind one? When we were kids and dumb it took all of 40,000 miles of infrequent towing to blow one of those up - the car had been a 60,000 mile Grandma car before that. A Buick with the Olds 307 in it. You'd have to have it custom built with beefed up guts I would think.
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